Sketch Plugins and Tools are software to import filters for the Sketch drawing package and tools for automating document conversion. Filters available include those for Drawfiles, Spritefiles and Impression documents.
The Sketch vector drawing application is a capable design tool, combining a familiar user interface with the flexibility of allowing extensions and plugins to be written in the Python language. This latter facility is very useful when extending the application's abilities to read information encoded in peculiar file formats through import filters as it allows rapid prototyping and experimentation, generating visible results quickly. Once the information is available to Sketch, the drawings and documents can then be manipulated or stored in convenient formats for future use.
Releasing information from legacy formats
Although the plugin facilities of Sketch are generally useful for interoperability with common document formats, I have a particular interest in reading documents stored in legacy or proprietary formats. This began because I required a degree of interoperability with various closed source applications but was also inspired by a realisation that, should my workstation cease to function, I would be unable to read many of my files on nearby incompatible workstations. Once the immediate danger of that possibility had diminished, and as development of the necessary import filters had reached a level of capability sufficient for my needs, I turned my attention to other formats in which my data was stored.
Two of the most common file formats in the RISC OS world are Drawfiles and Spritefiles. Because these file formats were well supported by their creator through various operating system facilities, many other applications (past and present) rely on data in these formats for display and storage purposes. The use of such file formats as "common currency" conveniently allows us to interpret data from more complex file formats through reuse of appropriate import filters and support libraries.
A good example of a more complex file format, in which some data is stored in its original format within a larger file, is the single file version of the Impression document format. This appears to provide support for only two types of picture format: Drawfiles and Artworks files. Since the Drawfile format allows Spritefiles to be embedded within drawings, they too can be imported into Impression's graphic frames using intermediate Drawfiles created to contain them.